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CD144 (VE-cadherin) is transiently expressed by fetal liver hematopoietic stem cells

Injune Kim, Ömer H. Yilmaz and Sean J. Morrison

Article Figures & Data

Figures

  • Figure 1.

    E13.5 fetal liver HSCs express the endothelial marker CD144 (VE-cadherin), but CD144 expression by HSCs declines over time and is no longer detected on adult bone marrow HSCs. (A) The frequency of CD144+ cells in the fetal liver declines over time. CD144 cells (red boxes) and CD144+ cells (blue boxes) were fractionated for functional studies. (B) Irradiated mice were competitively reconstituted with 1350 CD144+ cells or 48 650 CD144 cells from E13.5 liver, 500 CD144+ cells or 49 500 CD144 cells from E16.5 liver, and 2000 CD144+ cells or 198 000 CD144 cells from adult bone marrow. These cell doses were based on the proportion of CD144+ versus CD144 cells in 50 000 fetal liver cells, or 200 000 bone marrow cells as done in previous studies of marker expression by HSCs.18,21 The percentage of donor-derived myeloid (panels in B), B, and T (not shown) cells was analyzed in mice that underwent transplantation with CD144+ (blue lines) or CD144 (red lines) cells. Each line represents the level of donor myeloid cells in a mouse from 4 to 16 weeks after transplantation. The black line at 0.3% in each panel represents the background threshold observed in negative control mice, such that donor cell reconstitution could not be detected below this line. Mice that were long-term reconstituted by donor myeloid cells were always long-term multilineage reconstituted. The proportions of mice that became long-term multilineage reconstituted are indicated under each panel. (C) CD144 expression was analyzed in Sca-++LineageMac-1+ HSCs from E13.5 and E16.5 fetal liver and in Sca-1+Lineagec-kit+ HSCs from adult bone marrow.18,21

Tables

  • Table 1.

    Even when highly enriched fetal liver Mac-1+Lineage-Sca-1+ HSCs were tested, most HSC activity was in the CD144+ (VE-cadherin+) fraction at E13.5, but both CD144+ and CD144- fractions had HSC activity by E16.5

    Fetal liver Mac-1+Lin-Sca-1+ cellsMice that engrafted (%)Long-term multilineage reconstituted (%)Transient multilineage reconstituted (%)Oligopotent reconstituted (%)Frequency of HSCs
    E13.5 CD144- 5 of 8 (63) 1 of 8 (13) 2 of 8 (25) 2 of 8 (25) 1 in 38
    E13.5 CD144+ 9 of 11 (82) 5 of 11 (45) 3 of 11 (27) 1 of 11 (9) 1 in 8.8
    E16.5 CD144- 13 of 15 (87) 10 of 15 (67) 2 of 15 (13) 1 of 15 (7) 1 in 5.1
    E16.5 CD144+ 5 of 6 (83) 4 of 6 (67) 0 of 6 (0) 1 of 6 (17) 1 in 5.1
    • Five CD45.2+CD144-Mac-1+Lineage-Sca-1+ cells or CD144+Mac-1+Lineage-Sca-1+ cells from the E13.5 or E16.5 fetal liver were injected along with 200 000 CD45.1+ cells into lethally irradiated CD45.1+ mice. To be considered reconstituted, donor-type cells of a particular lineage had to represent greater than 0.3% of cells. Mice were considered long-term multilineage reconstituted when donor-derived myeloid, B, and T cells were observed in the blood for at least 6 months after reconstitution. Mice were considered transiently multilineage reconstituted if donor-derived myeloid, B, and T cells were observed in the blood, but donor-type myeloid cells could no longer be detected by 16 weeks. Oligopotent reconstitution was characterized by transient donor reconstitution of 1 or 2 lineages. The frequency of HSCs was calculated by Poisson limit-dilution statistics18,21 based on the frequency of mice that became long-term multilineage reconstituted.